Not recognized in their lifetime?

Hack, I agree Frank Zappa was very misunderstood. But what did you expect for someone who named his children Dweezil and Moon Unit?

My (often dim) recollection of stuff i heard in school does'nt put Bach in the starving artist category. The biographical account at- http://www.baroquemusic.org/bqxjsbach.html doesn't either. He was the Capellmeister of Weimar then Cothen and moved to take the same title at Leipzig (largely so his sons could attend a good university). "His arrival was clearly a major event in the musical and social world". The inagural ceremony was on May 31, 1723. At 36 he married a 20 year old, Anna Magdelena (one of the best sopranos in the country). "There is no doubt whatsoever that he was widely respected as a composer, musician, teacher and specialist in organ construction. This respect was to grow steadily as Bach's reputation widened and he gained the official title of Court Composer to the Dresden Court". His son Carl Phillip Emanuel wrote, "No musician of any consequence passing through Leipzig would fail to call upon my father", "where Bach had a large private music room in which he kept six claviers and several other instruments". He lived to be 65 when the average life expectancy was somewhere under 40.
This guy was a BIG player on the German music scene during his lifetime. I'm not saying he wasn't misunderstood or mistreated (everyone is at sometime), but his compositions got played. There are scores of great musicians and composers (living and dead) who have had to get by w/ alot less recognition, eg. (a tiny sample):

Stuart Liebig
Michael Vlatkovich
Michel Wintsch
Fred Frith
Edgard Varese
Don Van Vliet
Maarten Altena
Don Cherry
Kevin Norton
Andrew Hill
Louis Sclavis
Jean Derome
Ben Goldberg
Bill Noertker
Ken Vandermark (gets props, but not enough)
Franz Koglmann
Lucas Niggli
Devin Hoff
Charles Mingus
Thomas Chapin
Wayne Horvitz

you left out Tiny Tim and Minnie Pearl :)

From a view based strictly on recorded performances, Mahler, and to a lesser degree Sibelius, come to mind, especially Mahler, who's music sort of languished until Bernstein started promoting it in the early 60's.

My recollection of Bach's biography agrees with Duanegoosen's, but I was not sure enough to cite it. The story of Bach is that while he, and his children were well regarded in their times, there was a gulf of several centuries during which he was forgotten.